Circuit interrupter



p l 9, 1957 J. B. OWENS ETAL 2,788,418

CIRCUIT INTERRUPTER Filed March 22, 1954 3 Sheets-Sheet 1 Fig. l.

April 9, 1957 J. B. OWENS ET AL 2,788,418

CIRCUIT INTERRUPTER Filed March 22, 1954 3 Sheets-Sheet 2 United StatesCIRCUIT INTERRUPTER Pa., a corporation of Pennsylvania Application March22, 1954, Serial No. 417,622 17 Claims. (61. 200-148) This inventionrelates to circuit interrupters in general, and, more particulariy, toimproved interrupting devices for circuit interrupters of thefluid-blast type.

in United States patent application filed September 23, 1953, Serial No.381,937 by James B. Owens, and assigned to the assignee of the instantapplication, there is disclosed and claimed a novel form of circuitinterrupting device, particularly one of the load-breakdisconnecting-switch type, in which a main disconnecting-switch bladebridges a pair of spaced circuit terminals, and with which is associateda load-break interrupting device and an interrupter isolating blade torelieve the main switch blade from any arcing. it is one of the objectsof our invention to improve upon the interrupting structure described inthis application.

It is still a further object of our invention to provide an interrupterconstruction for forcing a blast of fluid against an established arc torapidly effect the extinction thereof.

A more specific object of our an improved puffer interrupting device inwhich movement of the movable contact is effective to actuate thedevice, and in which a blast of fluid is directed against theestablished arc to quickly bring about circuit interruption.

in United States patent application filed July 19, 1951, Serial No.237,592, now United States Patent 2,757,261, issued July 31, 1956, toHarry I. Lingal, Thomas E. Browne, in, and Albert P. Strom, and assignedto the assignee of the instant application, the use of a new gas forarc-extinguishing purposes is set forth and claimed, this gas beingsulfur hexafluoride (SP6), which exhibits phenomenal arc-extinguishingproperties. As set out in said application, it is advisable, in certainconstructural aspects, to use a fluorinated polymer insulating material,and particularly, solid fiuorocarbons, such as polytetraiiuoroethylene,polychlorotrifluOroethylene, or polyvinylfluoride, since none of thesematerials reacts with the products of decomposition of the gas, whensubjected to an arc, to form corrosive acids. However,polytetrafluoroethylene is quite expensive, being at the time of filingthis application approximately $14 a pound. To provide a puffer assemblyof this material is ere pensive, and if such a putter assembly is movedwithin a porcelain weather casing, or through a hollow cylinder ofceramic material, the weather casing or the cylinder of ceramic materialneeds to be machined to relatively close tolerances, all of whichincreases the expense of manufacturing such a device.

it is, therefore, a further object of our invention to provide aninexpensive puiier assembly, which, when used in conjunction with a gas,such as SP6, needs to employ only a relatively small quantity ofpolytetrafluoroethylene, polychlorotrifluoroethylene or polyvinylfluoride.

In addition, it has been found from a result of research tests thatprolonged scraping of the polytetrafluoroethylinvention is to provideatent O 2,788,418 Cc Patented Apr. 9, 1957 ene puffer on the porcelaintube formed a film that was susceptible to electrical breakdown. It is,therefore, still a further object of our invention to provide aneffective, relatively cheap puffer assembly, easy to manufacture, andproviding longer operational life while in service without danger ofdielectric breakdown.

An ancillary object of our invention is to provide an improvedconstructional mounting arrangement for a puffer assembly, particularlyone employing a relatively stationary piston.

Further objects and advantages of our invention will be readily apparentupon reading the following specification taken in conjunction with thedrawings, in which:

Figure 1 is a side elevational view of a circuit interrupter, of theload-break disconnecting switch variety, incorporating our invention andillustrated in the closed circuit position;

Fig. 2 is an enlarged, fragmentary, vertical sectional view through thecircuit interrupting device of Fig. l, the contact structure beinglikewise shown in the closedcircuit position;

Fig. 3 is an enlarged, fragmentary, vertical sectional view through theinterrupter casing of Fig. 2, the contact structure being illustrated inthe fully open-circuit position;

Fig. 4 is a fragmentary, sectional view taken along the line IV-IV ofFig. 3;

Fig. 5 is a plan view of one of the valve details of the interruptershown in Fig. 3; and

Fig. 6 is a plan view of a washer element employed in the valvestructure shown in Fig. 3 of the drawings.

Referring to the drawings, and more particularly to Fig. 1 thereof, thereference numerals 13 designate supporting porcelains, which extend, inthis particular instance, vertically upwardly from a channel-shaped basemember, not shown. As well known by those skilled in the art, thecircuit interrupter 4 may be mounted in either the horizontal position,as shown, or in an inverted position, or in a vertical position,depending upon the application requirements. Naturally, the particularmounting arrangement has nothing to do with our invention, and forpurposes of illustration, the load-break switch is illustrated in ahorizontal position. The supporting porcelain 2 is rotatable, and, whenrotated, serves to actuate a mechanism provided within a housing 5 toeffect first an axial rotative movement of the main switch movingcontact or blade 6 about its axis to reduce contact pressure between theend 7 of the blade 6 and the stationary main switch jaws 8, meanwhilebreaking any ice which may have formed thereat.

Subsequently, the mechanism disposed interiorly within the housing 5,when actuated by rotative motion of the rotatable insulator column 2,serves to bodily rotate the main switch moving contact 6 upwardly awayfrom the main stationary switch jaw contacts 8, separating therefrom sothat the circuit will then be compelled to pass through a circuitinterrupting device 10, which is mounted adjacent the switch jaws 8 uponsupporting insulator 1.

The tip end 11 of the main switch-blade 6 strikes a laterally juttingprojection 12 disposed at the end of a crank arm 13 to effect rotationof a drive shaft 14 to effect operation of an overcenter toggle springmechanism 15, disposed interiorly within a housing 16 positioned at theupper end or" the interrupting device 10.

During the time that the main switch blade 6 has separated from the jawcontacts 8, the main circuit extends from the terminal pad 17 to therelatively stationary contact 18 (Fig. 2), thence by way of the movablecontact 19 and through lift rod 20 to flexible connection 21, the otherend of which is secured, as at 22, to a portion of the conductinghousing 16. An upper stationary terminal iar'seais 23, more clearlyshown in Fig. 1, has a forked outer end, not shown, which receives theend 24 of the interrupter isolating blade 25, which .is biased by aspring assembly 26 in the direction, as indicated by the arrow 27,toward the main switch-blade 6. The lower end of the interrupterisolating blade 25 is pivotally mounted to the side wall of the camhousing 5, as indicated in Fig. 1. Thus, the circuit will pass throughthe interrupter isolating blade 25 to conducting cam housing 5 andfinally through support casting 9 to line terminal connection plate 28.

As will become more clear hereinafter, engagement of the projection 12by the tip end 11 of the main switchblade 6 causes rotation of the driveshaft 14 and actuation of the overcenter mechanism 15 to cause upwardseparating motion of the movable contact 19 (Fig. 2) away from therelatively stationary contact 18 to estabiish an arc therebetween. withthe contacts 18, 19 to effect a blast t fluid, inthis particularinstance a gas such as sulfur hexafiuoride, against the established arcto effect the extinction thereof. Subsequently, a laterally extendingarm 39, secured to and movable with the main switch blade 6, picks upthe interrupter isolating blade 25 and carries the latter therewith tothe fully open-circuit position of the device, as indicated by thebroken lines 31 of Fig. 1. In this position, the crank arm 13 is in theposition indicated by the broken lines 32. The interrupter is then fullyopen.

A pufier assembly 29 is associated During the closing operation, themain switch blade 6, I

together with the interrupter isolating blade 25, swing in acounterclockwise direction about the shaft 33 of the hinge end 34 of theload-break switch, being biased together by the spring assembly 26.During this closing movement, the tip 24 of the interrupter isolatingblade 25 first engages the forked end of the stationary terminal 23 atthe top end of the circuit interrupting device 10. The circuit throughthe interrupter 4 is not closed, however, because of the separatedcondition of the contacts 18, 19 at this time. Further,counterclockwise, closing rotative travel of the main switch movingcontact 6 causes the tip end 11 thereof to strike the projection 35,which in the position 32 is in the path of the end 11 of the switchblade 6. As a result, the tip 11 of the switch blade 6 forces theprojection 35, and hence, the crank arm 13, in a clockwise directionabout the drive shaft 14 to effect overcenter spring action of thetoggle mechanism 15 within the housing 16, to effect thereby snapclosing motion of the movable contact 19 against the upper end of thestationary contact 18. This will complete the circuit through theinterrupter 4, and continued travel of the main switch blade 6 willcause the contact end 7 thereof to slide between the spaced jaw contacts8, making contact therewith. Final rotative closing motion of therotatable insulator column 2 will effect axial rotative motion ofthemain switch-blade 6 to bring the wider dimension of the contact 7against the spaced jaws 8 to efiect their expansion, and thereby bringhigh contact pressure to bear between the contacts 7, 8. Thisnot onlyprovides a low resistance path through the interrupter 4, but alsoeffectively shorts out the circuit through the circuit interruptingdevice 10. I

The circuit interrupting device 10 is more clearly set out in Fig. 2 ofthe drawings. It will be noted that the putter device 29 includes arelatively stationary piston 36,

which cooperates with a movable operating cylinder 37, the latterpreferably being formed of aluminum tubing. The lower end of theoperating cylinder 37 is rolled, as at 38, into an indentation 38aprovided annularly about a spider member 39. The conducting spidermember 39 not only provides a support for the movable contact 19,

but also provides a plurality of apertures 41, through which gas maypass during the opening operation. It will be noted that disposed in theside walls of the operating cylinder 37 are a plurality of venting ports42,

opening travel of the operating cylinder 37.

Associated with the lower end of the movable operating cylinder 37 isorifice means 43, in this particular instance including an elongatedorifice member 44, of substantiaily tubular configuration, which isscrewed, as at 45 (Fig. 3), to a downwardly extending flange portion 46of the spider member 39. Preferably, the orifice member 44 is formedfrom polytetrafiuoroethylene, polychlorotrifluorcethylene or polyvinylfluoride, and has the length of its orifice 77 several times thediameter of the orifice to give most effective deionizing action. Ashield disc member 47 preferably of polytetrafluoroethylene,polychlorotrifluoroethylene, or polyvinyl fluoride is screwed, as at 43,to the end of the orifice member 44-. he shield 47 does not have to havea close fit within the interior the insulator column which does not haveto be machined as has been the case where the separate metal cylinder 37and piston 36 were not provided. The function of the shield is toprotect the metal parts above it from hot are products, rather than toact as a piston, and to prevent fiashover between the stationary contact13 and metal spider 39.

Preferably, valve means are associated with the stationary piston as, inthis instance comprising a washer 49, more clearly shown in Fi 6 of thedrawings, which seals the opening 50 through the piston 36 during upwardtravel or the operating cylinder 37 during the opening operation. Thewasher 49 is supported on an apertured ring shown in detail in Fig. 5 ofthe drawings, the latter being secured fixedly in place within adownwardly extending flange portion 52 of the stationary piston 36 bypeening over spaced portions of the flange member 52.

As a result, a valve, generally designated by the reference numeral 53,is associated with the stationary piston 36 functioning by fluidpressure to close the opening 50 during the upward driving motion or"the operating cylinder 37, and permitting, during t.e downward stroke ofthe operating cylinder 37, free flow of into the interior 5d of thecylinder 37 through the holes 55 of the apertured ring 51, as indicatedby the arrows 56 of Fig. 3.

The specific operating mechanism i5, disposed Within the housing 1-6,forms no part of our invention, except as it cooperates with the rest ofthe structure, and the general principles of operation thereof are setforth and claimed in United States Patent No. 2,769,063 issued October30, 1956 on an application filed October 26, 1951, Serial No. 253,321 byIarry .i. Lingal, entitled Circuit interrupting Device, and in thedivision of that application Serial No. 576,875 filed April 9, 1956,both assigned to the assignee of the instant application. Generally, theoperation is such that counterclockwise opening travel of the driveshaft 14 causes corresponding counterclockwise travel of a crank arm 57secured thereto and disposed interiorly within the mechanism housing 16.A floating link 58 connects the outer end 59 of the crank arm 57 withthe outer end of toggle arm to which one end of a tension spring 61 issecured. The toggle arm 69 rotates about a shaft 62, about which alsorotates a second toggle arm s3, to which, as at 64, the other end of thetension spring at is secured.

From the foregoing, it will be noted that the tension spring 61 is anovercenter tension spring which will effect snap opening and snapclosing of the contact structure. A support bracket 65 is secured to theupper end of the housing 16 on a pair of integral pedestal supports 66,67. To the outer end of the support bracket 65 is pivotally mounted, at68, a lever 69, to the lower end of which is pivotally connected, as at79, a floating lever '71, which is pivotally connected, as at 54, to thesecond toggle arm 63 of the mechanism 15. The lower end of the floatinglever 71 is pivotally connected, as at 72, to the upper end of the conact rod 2d. As well known by those skilled in the art, the foregoinglinkage insures substantially straight-line motion of the upper end ofcontact rod 20.

The general manner of operation of the overcenter toggle springmechanism 15 is as follows: counterclockwise rotation of the drive shaft14, as effected by the externally disposed crank-arm 13, effects throughthe linkage 58 corresponding counterclockwise rotation of the toggle arm60, and hence movement of the right-hand end 61 of the tension spring 61upwardly toward the center line 73 of the toggle mechanism 15. Nothinghappens until the line of action of the overcentcr spring 61 passes overthe center line 73 and begins to exert a torque upon the second togglearm 63 about the shaft 62. This will effect a snap action of the secondtoggle arm 63 in a clockwise direction about the shaft 52, to therebyeffect a counterclockwise rotative travel of the floating lever 71 aboutits pivotal connection with the guide lever 69. This all occurs with a.ap action, as effected by contraction of the tension spring so that thefloating lever 71 will be arrested A 74, as indicated by the dot-dashlines 75 of Fig. drawings.

The contact rod 20 will, by this means, be snapped to its upwardposition, carrying with it the entire operating cylinder 3'1 movablecontact 19 and orifice means $3. The upward movement of the operatingcylinder 37 will, because of the presence of the venting ports 42,effect no compression of gas within the interior of the operatingcylinder 37, but during this time the movable contact 19 will be pickingup speed and gathering kinetic energy. When the operating cylinder 37has traveled upwardly far enough during the opening operation, so thatthe venting ports 42 will have passed over the stationary piston 36,further upward movement of the operating cylinder 37 will effect acompression of the gas within the interior 54 of the operating cylinder37, which will forcethis compressed gas through the apertures s ofspider member 39 and adjacent the are 7a, which is drawn for purposes ofillustration in Fig. 3 of the draw logs. The compressed gas in passingalong the interior 77 of the orifice 44 will effect deionization of theare 76 and will effect the extinction thereof.

As mentioned, during this upward travel of the operat ing cylinder 37,the valve 53 will close. in other words, the washer 4? will be forced bythe gas pressure upwardly to effect closing of the opening 5% instationary piston 36.

During the closing stroke, the operating cylinder 37 is moved downwardlywith a snap action by the overcenter spring mechanism to effect rapidengagement between the contacts 19, 18 to complete the circuit throughthe interrupting device 19. During this downward movement of operatingcylinder 37, the gas will be sucked through the opening 5% and throughthe apertures 55 of apertured ring 51, the washer 49 remaining in itslower position, as indicated in Fig. 3, immediately adjacent the supportring 51.

From the foregoing description of our invention, it will be apparentthat the are 76 is effectively blasted by gas passing out of theoperating cylinder 37 and through the elongated orifice 44. It will benoted that the operating cylinder 37 is guided at two points. One pointwill be'between the piston 36 and the inner side wall of the operatingcylinder 37, and the other point will be at the pivotal connection 72 ofcontact rod Ltd.

From the foregoing description, it will be apparent that carefulmachining of the inside of the porcelain ing 30 is unnecessary, and theamount of polytetrafluoroethylene, polychlorotrifiuomethylene orpolyvinyl fluoride used is reduced. Also, no conducting films are formedalong the inner wall of the casino so, since the stationary piston 36and the straight-line motion of the contact rod provides essentially allthe guiding action nec'essaryfthe friction or rubbing action between the2 of the CES- by a sto pedestal 6 inner wall 79 of casing 80 and shielddisc 47 being negligible.

The stationary piston 36 has an integrally formed upstanding flangeportion 81, within which is positioned and welded the end of a metallictube 82. The upper end of the tube 82 is received within a recess 83 ofa nut 34, which threads, as at 85, into a tapped opening 86 provided ina mounting plate 87. Mounting bolts 88 secure the mounting plate 87 toan annular flange ring 89 cemented, as at 90, to the upper end 91 of theporcelain weather casing 80.

A gasket 92 is interposed between the end of casing 8i and the mountingplate 87 to provide a gas-tight construction, Additional mounting bolts93 secure the mounting plate 87 to a lower inwardly extending flangeportion of the mechanism housing 16. A gasket 95 provides a gas-tightconnection. The contact lift rod 26 extends interiorly through themetallic tube 82.

The relatively stationary contact 18 is disposed at the upper extremityof a contact rod 96 resiliently mounted to a metallic closure plate 97,the latter being secured by mounting bolts 98 to a flange ring 99. Theflange ring 99 is secured to the lower end 100 of the porcelain casing89 by cement 101. A gasket 102 provides a gastight connection.

The pressure of the gas within the casing 80 is measured by a gauge 1%and a gas inlet opening 104 is provided for supplying gas, such as SP6,into the casing 80 as more fully covered in the aforesaid applicationSerial No. 576,875. Mounting bolts 1G5 secure the closure plate to thesupport casting 1G6 supported by insulator column 1.

From the foregoing description, it will be noted that the fixed piston36 and the operating cylinder 37 are secured, or mounted from the tophousing 16. Thus upon removal of the mounting bolts 83, the entire tophousing 16 may be lifted away from the casing 80 carrying there with theentire puffer assembly 29. Obviously, this facilitates assembly anddisassembly of the interrupter 10. Similarly, the casing 80 may bedetached or attached to the closure plate 97, to which the stationarycontact rod. 96 is secured.

Although we have illustrated our invention as employing sulfurhexafiuoride gas with insulating structural members ofpolytetrafiuoroethylene, polychlorotrifiuoroethylene, or polyvinylfluoride, it is to be understood that some aspects of the invention maybe applied to other fluids, such as air, helium, carbon dioxide,nitrogen, etc., in combination with other insulating materials. In eachcase, the advantage of having the metallic walls of the operatingcylinder 37 provide the guiding function is evident.

Although we have shown and described a specific construction, it is tobe clearly understood that the same was merely for the purpose ofillustration, and that changes and modifications may be readily madetherein by those skilled in the art, without departing from the spiritand scope of the invention.

We claim as our invention:

1. The combination in a circuit interrupter of a sealed casingcontaining an arc-extinguishing gas comprising sulfur hexafluoride, arelatively stationary piston, a movable operating cylinder havingmovable orifice means of a fiuorinated polymer insulating materialdisposed adjacent one end thereof, a movable contact associated with theorifice means and secured to the movable operating cylinder to effectthe movement thereof, and the gas being forced during the openingoperation of the circuit interrupter out of the movable cylinder andthrough the orifice means to effect extinction of the are.

2. A circuit interrupter including a hollow sealed casing of insulatingmaterial containing an arc-extinguishing gas comprising sulfurhexafiuoride, a relatively stationary contact extending within thehollow casing adjacent one end thereof, a relatively stationary pistonextending into the other end of the hollow casing, a movable operatingcylinder surrounding the relatively stationary piston and creams havinga movable contact secured thereto, the contacts being separable toestablish an arc, and opening movement of the movable contact andoperating cylinder forcing gas comprising sulfur hexafluoride againstthe established arc to effect the extinction thereof.

3. A circuit interrupter including a hollow sealed casing of insulatingmaterial containing an arc-extinguishing gas comprising sulfurhexafiuoride, a relatively stationary contact extending within thehollow casing adjacent one end thereof, a relatively stationary pistonextending into the other end of the hollow casing, a movable operatingcylinder surrounding the relatively stationary piston and having amovable contact secured thereto, an orifice of a fluorinated polymerinsulating material secured to and movable with the operating cylinder,the movable contact being disposed within the orifice, separation of teecontacts establishing an are within the orifice, and opening movement ofthe movable contact and operating cylinder forcing gas from within theoperating cylinder through the orifice and against the established arcto efiect the extinction thereof.

4. A circuit interrupter including a tubular casing of insulatingmaterial containing sulfur hexafiuoride gas, a relatively fixed pistonmounted in the tubular casing, a

movable operating cylinder containing an orifice and shield disc of afiuorinated polymer insulating material, a relatively stationary contactdisposed within said tubular casing, a cooperable movable contactdisposed within the orifice and movable with the movable operatingcylinder, said contacts being cooperable to establish an arc,

and sulfur hexafiuoride gas being compressed out of the operatingcylinder through the orifice and against the arc to effect theextinction thereof.

5. A circuit interrupter including a tubular casing of insulatingmaterial containing sulfur hexafiuoride gas, a relatively fixed pistonmounted in the tubular casing, a movable operating cylinder containingan orifice of a polymer of fluorinated ethylene selected from the groupconsisting of polytetrafiuoroethylene and polychlorotrifluoroethylene, arelatively stationary contact disposed Within said tubular casing, acooperable movable contact disposed Within the orifice and movable withthe movable operating cylinder, said contacts being cooperable toestablish an arc, and sulfur hexafiuoride gas being compressed out ofthe operating cylinder through the orifice and against the arc to effectthe extinction thereof.

6. A circuit interrupter including a sealed casing containing a fixedquantity of arc-extinguishing gas, said casing including a tubularmember of insulating material, a fixed piston, a supporting memberextending into the tubular member from one end thereof and supportingthe fixed piston, a cylinder supported from the same end of the tubularmember and movable over the fixedpiston, a relatively stationarycontact, a movable contact carried by the movable cylinder andcooperable with the relatively stationary contact to establish an arc,and gas compressed within the movable cylinder by the fixed piston beingforced into the arc to facilitate the extinction thereof.

7. A circuit interrupter including a sealed casing containing a fixedquantity .of arc-extinguishing gas, said casing including a tubularmember of insulating material, a fixed piston, a supporting memberextending into the tubular member from one end thereof and supportingthe fixed piston, a cylinder supported from the same end of the tubularmember and movable over the fixed piston, said cylinder havingrelatively small clearance with respect to the inner wall of the tubularmember, a relatively stationary contact extending into the tubularmember from the other end thereof, orifice means carried by the movablecylinder, a movable contact carried by the movable cylinder andcooperable with the relatively stationary contact to establish an arc,and gas compressed within the movable cylinder by the fixed piston beingforced through said orifice means and into the arc to facilitate theextinction thereof,

8. A circuit interrupter including a sealed casing containing a fixedquantity of arc-extinguishing gas, said casing including a tubularmember of insulating material, a fixed piston, a supporting memberextending into the tubular member from one end thereof and supportingthe fixed piston, a cylinder supported from the same end of the tubularmember and movable over the fixed piston, a relatively stationaryrod-shaped contact disposed adjacent the other end of the tubularmember, an orifice carried by the movable cylinder, a movable contactcarried by the movable cylinder and disposed within said orifice, therelatively stationary and movable contacts being cooperable to establishan arc, the rod-shaped relatively stationary contact extending into theorifice in the closed circuit position of the interrupter, and gascompressed within the movable cylinder by the fixed piston being forcedthrough the orifice into the arc to extinguish the same with the orificebeing movable over the end of the rod-shaped stationary contact.

9. A circuit interrupter including a sealed casing containing a fixedquantity of arc-extinguishing gas comprising sulfur hexafiuoride, saidcasing including a tubular member of insulating material, a fixedpiston, a supporting member extending into the tubular member f om oneend thereof and supporting the fixed piston, a cylinder supported fromthe same end of the tubular member and. movable over the fixed piston, arelatively stationary contact, a movable contact carried by the movablecylinder and cooperable with the relatively stationary contact toestablish an arc, and gas comprising sulfur hexafiuoride compressedWithin the movable cylinder by the fixed piston being forced into thearc to facilitate the extinction thereof.

10. A circuit interrupter including a sealed casing containing a fixedquantity of arc-extinguishing ga comprising sulfur hexafiuoride, saidcasing including a tubular member of insulating material, a fixedpiston, a supporting member extending into the tubular member from oneend thereof and supporting the fixed piston, a cylinder supported fromthe same end of the tubular member and movable over the fixed piston,said cylinder having relatively small clearance with respect to theinner wall of the tubular member, a relatively stationary contactextending into the tubular member from the other end thereof, orificemeans of a fiuorinated polymer insulating material carried by themovable cylinder, a movable contact carried by the movable cylinder andcooperable with the relatively stationary contact to establish an arc,and gas comprising sulfur hexafiuoride compressed Within the movablecylinder by the fixed piston being forced through said orifice means andinto the arc to facilitate the extinction thereof.

ll. A circuit interrupter including a sealed casing containing a fixedquantity of arc-extinguishing gas comprising sulfur hexafiuoride, saidcasing including a tubular member of insulating material, a fixedpiston, a supporting member extending into the tubular member from oneend thereof and supporting the fixed piston, a cylinder supported fromthe same end of the tubular member and movable over the fixed piston, arelatively stationary rod-shaped contact disposed adjacent the other endof the tubular member, an orifice of a fluorinated polymer insulatingmaterial carried by the movable cylinder, a movable contact carried bythe movable cylinder and disposed within said orifice, the relativelystationary and movable contacts being cooperable to establish an arc,the rod-shaped relatively stationary contact extending into the orificein the closed circuit position of the interrupter, and gas comprisingsulfur hexafiuoride compressed within the movable cylinder by the fixedpiston being forced through the orifice into the arc to extinguish thesame with the orifice being movable over the end of the rodshapedstationary contact.

12. The combination in acircuit interrupter of a sealed casingcontaining a fixed quantity of arc-extinguishing gas, said casingincluding a tubular member of insulating material, a fixed piston, asupporting member extending into the tubular member from one end thereofand supporting the fixed piston, a cylinder supported from the same endof the tubular member and movable over the fixed piston, said movablecylinder supporting an elongated tubular orifice, a movable contactdisposed adjacent one end of the tubular orifice and carried by themovable cylinder, a relatively stationary contact extending into thetubular member from the other end thereof and extending in the closedcircuit position of the interrupter through the tubular orifice toengage the movable contact, during the opening operation the tubularorifice being movable with the movable cylinder 50 that the relativelystationary contact traverses the length of the tubular orifice, and thetubular orifice then moves away from the end of the relativelystationary contact.

13. The combination in a circuit interrupter of a sealed casingcontaining a fixed quantity of arc-extinguishing gas comprising sulfurhexafiuoride, said casing including a tubular member of insulatingmaterial, a fixed piston, a supporting member extending into the tubularmember from one end thereof and supporting the fixed piston, a cylindersupported from the same end of the tubular member and movable over thefixed piston, said movable cylinder supporting an elongated tubularorifice of a fluorinated polymer insulating material, a movable contactdisposed adjacent one end of the tubular orifice and carried by themovable cylinder, a relatively sationary contact extending into thetubular member from the other end thereof and extending in the closedcircuit position of the interrupter through the tubular orifice toengage the movable contact, during the opening operation the tubularorifice being movable with the movable cylinder so that the relativelystationary contact traverses the length of the tubular orifice, and thetubular orifice then moves away from the end of the relativelystationary contact.

14. The combination in a circuit interrupter of a tubular casing sealedfrom the ambient air and containing an arc-extinguishing gas comprisingsulfur hexafiuoride, a relatively stationary piston disposed within saidtubular casing adjacent one end thereof, a movable operating cylinderhaving movable orifice means of a fluorinated polymer insulatingmaterial disposed adjacent one end thereof, a movable contact associatedwith the orifice means and secured to the movable operating cylinder toeffect the movement thereof, a relatively stationary contact positionedadjacent the other end of said tubular casing, the movable contact beingcooperable with said relatively stationary contact to establish an arewithin said orifice means, and the gas being forced during the openingoperation of the circuit interrupter out of the movable cylinder andthrough the orifice means to effect the extinction of the are.

15. A circuit interrupter including a hollow tubular casing ofinsulating material sealed from the ambient air and containing anarc-extinguishing gas comprising sulfur hexafiuoride, a relativelystationary contact extending within the hollow tubular casing adjacentone end thereof, a relatively stationary piston extending into the otherend of the hollow tubular casing, a movable operating cylindersurrounding the relatively stationary piston and having a movablecontact secured thereto, movable orifice means associated with saidmovable contact, the contacts being separable to establish an arethrough said orifice means, and opening movement of the movable contactand operating cylinder forcing gas comprising sulfur hexafiuorideagainst the established are within said orifice means to effect theextinction thereof.

16. A circuit interrupter including a casing sealed from the ambient airand containing a quantity of arc-extinguishing gas, said casingincluding a tubular member of insulating material, a relatively fixedpiston, a supporting member extending into the tubular member from oneend thereof and supporting the relatively fixed piston, a movablecylinder supported from the same end of the tubular member and movableover the relatively fixed piston, a relatively stationary contactprojecting into the other end of said tubular member of insulatingmaterial, a movable contact carried by the movable cylinder andcooperable with the relatively stationary contact to establish an arc,and gas compressed within the movable cylinder by the relatively fixedpiston being forced into the arc to facilitate the extinction thereof.

17. A circuit interrupter including a casing sealed from the ambient airand containing a quantity of arc-extinguishing gas, said casingincluding a tubular member of insulating material, a relatively fixedpiston, a supporting member extending into the tubular member from oneend thereof and supporting the relatively fixed piston, a movablecylinder supported from the same end of the tubular member and movableover the relatively fixed piston, said movable cylinder havingrelatively small clearance with respect to the inner Wall of the tubularmember, a relatively stationary contact, a movable con-tact carried bythe movable cylinder and cooperable with the relatively stationarycontact to establish an arc, and gas compressed within the movablecylinder by the relatively fixed piston being forced into the arc tofacilitate the extinction thereof.

References Cited in the file of this patent UNITED STATES PATENTS

